Treatment of chain links



Patented Apr. 24, 1945 TREATMENT OF CHAIN LINKS Henry St. Pierre, Worcester, Mass.

Application October 3, 1944, Serial No. 556,992

Claims.

This invention relates to method and apparatus for heat treating and normalizing links assembled in a chain,

Objects of the invention include the provision of method and means for heat treating any link in a chain of links without afiecting the metallurgical properties of the next adjacent links; the pro- Vision of method and means for heating any link in a, chain to a desired degree while avoiding the heating of next adjacent links at least sufiiciently to prevent change in grain characteristics or other metallurgical properties thereof; and the provision of means and method for heat treating and normalizing repair chain links as by flame-hardening, electric or other heating while at the same time avoiding detrimental heating of adjacent links already having the desired hardness and toughness.

Other objects and advantages will appear herematter.

In the drawing Fig. l is a plan view of a device illustrating a method for carrying out the invention;'

Fig. 2 is a view in side elevation of Fig. 1, parts being in section, and Fig. 3 is a view illustrating a modification of the invention.

In the manufacture of chain particularly of the heavy duty type, it is sometimes necessary to replace a faulty link. Theentire chain having been heat treated, and the repair link necessarily being soft, the problem arises of heat treating and normalizing the repair link without damaging the adjacent links thru incidental application of unwanted heat thereto.

The present invention resides in the concept of spacing the two adjacent links from the replacement link being treated, to prevent conduction of heat from the latter to the former. Radiant and convection heating are only minor and since a normal heat of several hundred degrees will not affect the already heat treated links, it follows that prevention of conducted heat will accomplish the result desired in a practical manner.

One method here presented resides in providing spacers of generally non-conductive material to slip in between adjacent portions of the replacement and connected links. Such spacers may be .plain bits of material or in the form of collars, etc.

However, another practical method is illustrated in the drawing wherein there is shown a plate I 0 mounting in fixed relation thereon three blocks I2, these blocks being parallel and equally spaced and extending from near one end I4 of the plate to a point intermediate the ends l4, 16 thereof.

Vertical pins is are fixed in the plate and are located between the blocks l2 adjacent the plate end is. A series of studs 20 extend vertically upwards in the arrangement shown in Fig. 1, these studs all being located beyond the ends of the blocks [2.

Link 22 is the replacement or joining link to be heat treated. The next adjacent links 24 are al ready in final heat treated condition and swung to parallel position and placed in the spaces between blocks l2, the latter maintaining these links in upright condition. The link 22 is placed to rest on the studs 20 which provide a four point support so that link 22 i supported only at these points and elsewhere is free of any contact.

' The studs correctly position the link 22, and links 25 are moved to contact pins l8, the latter providing that ends 26 are free and clear of any contact with the link 22, thus providing an insulating air space between the latter and the links At the same time, link 22 is supported at spaced points only and cannot transmit heat by conduction to the plate I6 or to the links 24, so that the link 22 may be treated as by a flame or electricity without damage to the properties of the metal of the adjacent links. Fig. 3 illustrates a link 30 held on pins 20 and hooked in with a link 32. Since the link 30 is being flame treated, link 32 is provided with an insulating collar 34.

It is to be understood that the apparatus and method here shown are merely illustrative and that other means and methods may be used for the same purpose, as specifically described above at the outset.

I claim:

1. Method of heating a link of a chain while maintaining the adjacent links relatively cool by spacing the said link from the adjacent links and applying heat to the said link.

2. Method of claim 1 including insulating the said link from the spaced adjacent links.

3. Method of heating a, link of a chain while maintaining the adjacent links relatively cool by 5. Method of heat treating a link of a chain' while maintaining the next adjacent links sumciently cool to avoid change of their properties including the steps of supporting the link at spaced points, supporting the next adjacent links in positions wherein their end portions pass thru the eye of the link without touching the same, holding the said next adjacent links in such position, and applying heat to the link,

HENRY ST. PIERRE. 

